Assessing the effects of modality of surgery on postoperative weight loss in patients undergoing partial nephrectomy

To compare the early BMI changes postoperatively between patients undergoing open partial nephrectomy (OPN) and robotic partial nephrectomy (RPN). Patients undergoing open NSS for a single renal tumor between 2010 and 2013 were retrospectively selected for the study. These patients were matched with RPN patients based on preoperative BMI and tumor R.E.N.A.L nephrometry score (1:1 matching). A total of 568 patients (284 pairs) met our inclusion criteria. The median time to lowest BMI was comparable between the OPN and RPN groups (24 vs. 29 days; p = 0.7). The mean BMI preservation was lower for the OPN group (96.8 +/- 4.4 vs. 98.1 +/- 4.7 %). On multivariable analysis after controlling for age, CCI, gender, tumor size, nephrometry score, estimated blood loss, occurrence of major complications and preoperative renal function, the modality of surgery favoring the RPN approach and the occurrence of major complications remained significant predictors for BMI preservation after surgery. Occurrence of major complications is associated with weight loss after NSS. Minimally invasive NSS delivered by RPN had lower impact on BMI loss in patients undergoing the procedure compared to OPN. This finding further suggests that RPN delivers minimally invasive surgery beyond the boundaries of just smaller incision sites.